2D Enzyme Cascade Network with Efficient Substrate Channeling by Swinging Arms

In living cells, compartmentalized or membrane‐associated enzymes are often assembled into large networks to cooperatively catalyze cascade reaction pathways essential for cellular metabolism. Here, we report the assembly of an artificial 2D enzyme network of two cascade enzymes—glucose‐6‐phosphate dehydrogenase (G6PDH) and lactate dehydrogenase (LDH)—on a wireframe DNA origami template. Swinging arms were used to facilitate the transport of the redox intermediate of NAD⁺/NADH between enzyme pairs on the array. The assemblies of 2D enzyme networks were characterized by gel electrophoresis and visualized by atomic force microscopy (AFM). The spatial arrangements of multiple enzyme pairs were optimized to facilitate efficient substrate channeling by exploiting the programmability of DNA origami to manipulate the key parameters of swinging arm length and stoichiometry. Compared with a single enzyme pair, the 2D organized enzyme systems exhibited higher reaction efficiency due to the promoted transfer of intermediates within the network.     

Sustainable control strategies for plant protection and food packaging sectors by natural substances and novel nanotechnological approaches

An overview is provided of the current technological strategies (also at the nanoscale level) recently involved in plant and/or food protection. In addition, the potential use of natural and sustainable substances, instead of traditional synthesized molecules or chemical-based compounds, is addressed both with respect to packaging systems and novel pesticide formulations. In this context, nanotechnological approaches represent promising strategies for the entire agriculture industry chain, from the field to consumers. Traditional plant protection strategies are often insufficient and the application of chemical-based pesticides has negative effects on animals, humans and the environment. Novel greener tools could represent efficient alternatives for the management of plant diseases using promising strategies; the use of nanotechnologies allows the promotion of the more efficient assembly and subsequent release of environmentally sustainable active principles, limiting the use of chemicals in terms of economic losses. At the same time, new sustainable, antimicrobial and antioxidant systems have been rapidly promoted and investigated in the food packaging sector as a valid eco-friendly possibility for improving the safety and quality of food products and reducing and/or limiting the environmental impact with respect to traditional materials. Together, the scientific community and the growing interest of consumers have promoted the development of new edible and eco-friendly packaging that reduces waste and any environmental impact. In this context, the aim is to provide evidence of the usefulness of strategies aiming to limit agrochemicals, as well as the potential of nanomaterials, in sustainable plant and food protection for agriculture management and the packaging sector. © 2018 Society of Chemical Industry     

Charge Migration in Organic Materials: Can Propagating Charges Affect the Key Physical Quantities Controlling Their Motion?

Charge migration is a ubiquitous phenomenon with profound implications throughout many areas of chemistry, physics, biology, and materials science. The long-term vision of designing functional materials with tailored molecular-scale properties has triggered an increasing quest to identify prototypical systems where truly molecular conduction pathways play a fundamental role. Such pathways can be formed due to the molecular organization of various organic materials and are widely used to discuss electronic properties at the nanometer scale. Here, we present a computational methodology to study charge propagation in organic molecular stacks at nano and sub-nanoscales and exploit this methodology to demonstrate that moving charge carriers strongly affect the values of the physical quantities controlling their motion. The approach is also expected to find broad application in the field of charge migration in soft matter systems.     

Matter Timed

At best, the ageing of materials is regarded as lending a patina to historic buildings. In reality, however, materials often age disgracefully and unevenly, requiring a high level of maintenance and refurbishment. What if materials could be engineered and integrated into buildings not only to enhance but to heal? Martina Decker , Assistant Professor in the College of Architecture and Design at the New Jersey Institute of Technology (NJIT), looks at pioneering research that is being undertaken into performative, time-dependent materials.     

纳米技术在挥发性有机废气处理中的应用研究

在简要介绍了纳米技术、纳米材料以及VOCs处理技术的基础上,概述了纳米技术在VOCs处理中应用方向,重点综述了近年来纳米光催化技术、纳米热催化技术、纳米吸附技术和纳米综合处理技术在VOCs处理中的应用研究进展,并指出了今后应着重研究的几个方面,旨在促进其相关研究的发展。     

Tungsten hexacarbonyl and hydrogen peroxide as precursors for the growth of tungsten oxide thin films on titania nanoparticles

W(CO)₆ and H₂O₂ were used in an atomic layer deposition (ALD)‐like process to grow thin WO_x films onto TiO₂ powders in a fluidized bed reactor. Carbonyl precursors are not widely used in this application, so that deviations from an ideal ALD process, previously not examined with W(CO)₆, were identified. The resulting WO_x films were a result of both ALD‐like and chemical vapor deposition‐based growth modes. A chemical reaction mechanism incorporating a combination of these two growth modes was inferred. As the move to expand the range of ALD precursors meets with the desire to scale up these processes, the simultaneous appearance of both these growth modes is likely to become more and more common, and so understanding the interaction of these two types of surface reactions is key to progress in the field. The films were observed to inhibit the anatase‐to‐rutile phase transformation in the TiO₂ powders upon high temperature annealing, while crystallization of the amorphous WO₃ was also not observed. Changes in the local bonding within the WO₃ were observed and associated with changes in the structural nature of the film and its interface to the substrate. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1278–1286, 2014     

锂离子电池纳米正极材料的研究进展

综述了近年来纳米技术在锂离子电池正极材料中应用的最新进展,重点阐述了纳米LiCoO2、LiMn2O4及LiFePO4等正极材料的制备及其性能.纳米正极材料的制备方法主要有溶胶-凝胶法、共沉淀法、模板法及水热法等,电极材料的纳微米化对锂离子电池的电化学性能和循环性能的改善有着显著的意义.     

基于核酸适配体的光学纳米传感器在食源性致病菌检测中的应用

食源性疾病一直严重威胁着世界各国人民的健康,而病原菌是引起这类疾病的主要原因。快速、简单、灵敏地筛选食源性致病菌对保证食品安全具有重要意义。纳米材料因其光学特性、独特的结构和催化性能、良好的稳定性和优异的穿透性,已成为近年来光学传感研究的热门课题。作为传感器的信号转换装置和生物识别分子的负载基质,纳米材料具有比表面积大、表面自由能高、生物相容性好、表面官能团丰富等特点。适配体是通过体外筛选的短单链核酸,具有合成简单、稳定性好、亲和力高、选择性强、适用性广等优点,是生物应用中理想的分子受体。利用基于适配体的光学纳米传感器检测食源性致病菌,克服了传统检测方法的耗时费力、难以定量、不便现场检测等缺点,成为当前食源性致病菌快速检测的研究热点。因此,本文综述了食源性疾病的流行现状,基于适配体的光学纳米传感器检测食源性致病菌的最新进展,重点介绍了细菌捕获方法和传感技术,以及它们各自的优势和局限性,提出了该技术在实际应用中面临的挑战和前景,以便促进该领域的进一步发展。